[MF3D.FORUM:137] Re: Light for viewer question

[Tloc54452@xxxxxxx]

In a message dated 2000/02/01 23:54:50, thubin@xxxxxxxxx writes:

>I think that what you are saying is that the far field appears bluish
>white near the center but maybe yellowish near the perimeter. The near
>field may have a somewhat different color distribution. 

You are correct, sir.  How are the Nichias?


In a message dated 2000/02/01 23:54:18, thubin@xxxxxxxxx writes:

>Imaging the LED so that it ends up at your eye would be much more
>efficient than using a diffuser. That requires that you place the LED
>far enough behind the slide so that the beam illuminates the slide
>evenly. Then a lens just before the light hits the slide. The lens
>should image the LED through the eyepiece and end up at the exit pupil
>of the eyepiece. That is where your eye is.
>
>Place a piece of paper where your eye would be. Remove the slide. You
>should see a projection of the LED itself on the paper. If so, then all
>light passing through the slide will enter your eye. No light wasted.

This is excellent.  I would say you want a fairly large spot focussed at 
the eyepoint so that eye placement is not critical.

John B